My '02 C32 has green coolant. I usually drain the radiator and refill it once a year rather doing a complete flush every two years. When I returned home from the dealership with a few gallons(part #q-1-03-0002) I noticed they were orange.

I read the green vs. orange in the MBCA Technical Library but gave no insight because it came with the green stuff from the factory.

I called the MB dealership and mentioned my dilema. They said that both green and the orange/yellow are combatible. Mixing should not be a problem. The person at the parts counter said that the green coolant comes from the factory and he did not even have any in stock. I asked him jokingly doesn't green and yellow make brown?

The factory stuff for the last 3 or more years has been dark blue, I think if you would use a freezing point gauge to check it, you'd see it's blue. Or just get some on a clean white paper towel.
As far as i know it's compatable, at least I haven't heard info to the contrary. We're still getting the yellow stuff from MB, I don't know if MB is selling the blue antifreeze in the US or not.

I agree with Gilly. The new cars have blue coolant, but only the familiar yellow stuff is available over the counter. I've had to mix them several times and haven't had any problems. Don't worry about it.